Jim Edson University of Connecticut Doug Vandemark & Amanda Plagge University of New Hampshire
Sea surface salinity from space: new tools for the ocean color community Joe Salisbury, Doug...
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Transcript of Sea surface salinity from space: new tools for the ocean color community Joe Salisbury, Doug...
Sea surface salinity from space:
new tools for the ocean color community
Joe Salisbury, Doug Vandemark, Chris Hunt, Janet Campbell, Dominic Wisser, Tim Moore (UNH)
Nico Reul, Bertrand Chapron (IFREMR)
• Aquarius and SMOS
• AMSR-E: the first SSS product from space
• Preliminary biogeochemical studies using remotely-sensed SSS and ocean color
• Can the ocean color community help the SSS community?
Outline:
Importance: From the NASA Aquarius website:
- Salinity has been sparsely detected at sea, limited mostly to summertime observations in shipping lanes: about 25% of the grid over ice-free oceans have never been sampled
- Aquarius will collect more data in two months than had been amassed by ships and in-water sensors during the 100 years before launch
NODC WOA-09 Atlas. Antonov et al., 2010
The data-related goals of Aquarius are:
1. Provide the first global observations of SSS, covering Earth's surface once every 7 days
2. Deliver monthly 150-kilometer resolution SSS maps over a 3-year mission lifetime
3. Achieve SSS accuracy of 0.2 psu
SSS retrievals from EOS AMSR-E
“Demonstration of ocean surface salinity microwave measurements from space using AMSR-E data over the Amazon plume”
N . Reul, et al. (2009) Geophysical Research Letters. V. 36, L13607, doi:10.1029/2009GL038860
Nevertheless: we found a robust salinity in tropical waters (SST>26C), using 10.7GHz6.8GHz
BvBv TT −TB=Sensitivity of Tb to several ocean and atmospheric variables
AMSR-E used to generate monthly SSS maps (2003-2009)(0.25 degree from ~56km original data)
ARGO
TSG averaged @ 0.25° resPIRATA
AMSR-E SSS product validation: match-up with in situ data compiled monthly (2003-2008)
Drifters
Rms<1.5 psu reportedPresent rms ~0.7 psu
Preliminary studies using AMSR-E SSS and ocean color data
Merged SeaWiFS-MODIS GSM log(acdm443)
Focus on the western tropical Atlantic with SSS and ocean color:
Manuscript: “Spatial and temporal coherence between Amazon discharge, salinity and
light absorption by colored organic carbon in the surface western tropical Atlantic.”
Comparison of seasonal climatologies (2003-2007)
Time series of ocean color and salinity along plume trajectoriesAnalysis locations based on segments of low salinity plume trajectory (proximal: 0-600km, distal: 1200-1800km)
Monthly time-series of discharge, AMSR-E SSS, and acdm443
along the plume trajectory from the 1200 -1800km
Can we use AMSR-E SSS and ocean color data to further our knowledge of ocean biogeochemistry?
Preliminary study of acdm anomalies along the Amazon plume trajectory
Preliminary study of acdm anomalies along the Amazon plume trajectory
- For each month in the time series, we considered a conservative relationship between salinity and acdm443.
(Only along the low-salinity trajectory of the plume)
- Plotted salinity versus the anomaly of the SSS -acdm443 relationship
- Analyzed the anomalies in terms of distance from Amazon mouth and ocean color variables.
Evidence for acdm photobleaching?
Salinity, residuals of linear regressions, distance from source
Evidence for “autotrophic”subsidies of acdm?
RESULT: A NEW SSS PRODUCT with rms < 1 psu in tropical waters to complement SMOS & AQUARIUS (and go back to 2002)
AMSR-E data available now for evaluating:
• Spatial SSS structure
• Temporal SSS signatures over a 8 year period
• Blending of satellite products using ocean color, AMSR-E, Aquarius, SMOS, SST
• Land-ocean interaction studies near tropical river plume regions and open ocean rain pools
Can ocean color help the SSS community?
The grid is the approximate resolution of monthly Aquarius data (150km),
..and the buffer is about 2 pixels (300km)
salinity
Intermediate steps: AMSR-E can help resolve within-pixel variability in warm waters
salinity
Intermediate steps: AMSR-E can also get closer to the coast
Merged product: AMSR SSS (left) and SSS <34 estimated from acdm443 (right)
• Create global AMSR-E SSS product for >26C (Indian Ocean underway!)
• Characterize regional variability in relationships between salinity and absorption
• Study effects of photobleaching and autotrophy on conservative mixing anomalies
• Pray for a successful Aquarius launch
What’s next?
• US researchers funded by NASA
• NASA Carbon Grant (NNX08AL8OG), J. Salisbury, PI
• NASA Ocean Sci. Salinity Team Grant (OSST-143304), D. Vandemark, PI
Acknowledgements
Thanks for listening!
GeoCAPE info/input meeting during lunch
EXTRA SLIDES
Comparison of seasonal climatologies (2003-2007)
Monthly time-series of discharge, AMSR-E SSS, and acdm443
along the plume trajectory from the mouth to 600km
Figure 6.
Localized 2.5 x 2.5°slope and intercept of salinity and acdm443
Slope and intercept (contour)
Salinity acdm443
Note that there’s increasing color per unit salinity here
Monthly AMSR-E climatological SSS products over period 2003-2008